Wenger became known in the final years of his Arsenal tenure for the long, padded coats -- with difficult fasteners -- he sported on the sidelines.

Some say it began with Arsene Wenger, the Arsenal icon, on Oct. 16, 2010, against Birmingham City, when he wore a full-length, five-partition Nike Storm Fit winter coat that came down to his knees -- a foot longer than his puffy jacket from the previous season. Some say Jose Mourinho's assistant coach at Inter, Daniele Bernazzani, wore a big down puffer before Wenger did, early winter 2010, at the Coppa Italia. Some say it was Mourinho, who wore his at Chelsea practice, sometime before March that same year.

Some say it just sprang up and finding a patient zero for the long soccer parka, a universal and infamous piece of clothing, is like trying to trace the first player to wear colored cleats.

Soccer is a copycat sport. It might have been Mourinho or Wenger who went first -- there's also a fair shout for Malcolm Allison, who managed Manchester City and Crystal Palace in the 1970s, as the first true parka-wearer in English soccer -- but in the past decade it's become a movement, with downy coats stretching across Europe and into the Americas.

England gets frigid in the winter; soon after the jackets bubbled up there, they ended up across top-flight European leagues. While managers' need for warmth wasn't taken seriously at first -- the meme economy was lousy with jokes about Wenger's long jacket and its correlation with missing titles -- the jackets were too practical to ignore.

Parkas cut for the pitch have since spread beyond soccer to high fashion. But they're not really found in the stands and are not easily available for fans to buy. In fact, they're barely sportswear and mostly produced now, without club logos, by fashion houses in Milan and Paris. Why does an infamous piece of club merchandise only sell in odd, remaindered sizes, in modified versions, in second-hand stores or showcase them on catwalks?

The New York Times ran a story about soccer managers' ugly coats shortly after a definitive Wenger meme went viral, a zipper malfunction during a 2012 Arsenal win over Newcastle. The story singled out Wenger, Sir Alex Ferguson and Rafael Benitez as ill-dressed; Roberto Mancini, Mourinho and Andre Villas-Boas were suave by comparison. Sarah Lyall, the Times' London correspondent who wrote the story, identified three archetypes: the "East German apparatchik, suave Italian and slob in a tracksuit." Wenger's long down coat, worn oversized, had an Eastern Bloc chicness to it but six years ago, it was "aggressively unstylish." The paper described Wenger's parka as "oddly elongated, sausage-like... makes him look like a caterpillar... [a] multizippered, hooded curiosity."

In a phone interview, Lyall said stylish dress was one way Premier League coaches made their authority over players more absolute. Natty Europeans seemed to do what basketball coaches do here, "[priding] themselves on being super sharply dressed as a way of exerting some sort of authority over the pitch when they were coaching." It's a type of fear through style.

Lyall told me she focused on Wenger's jacket since it was "a source of huge amusement and ridicule for both Arsenal fans and non-Arsenal fans." As she saw it, his parka overshadowed his suits. She also preferred Mancini's slim-fitting, nonchalant style, and then-Exeter boss Paul Tisdale's overcoats and foulards, to the slovenly tracksuits worn by some coaches. Still, a long down jacket is a better career move than an umbrella and in the past decade, it's become a feature across soccer.

Beckham is also known for his segue into style and fashion but never to the extent of wearing the long jackets that got Wenger plenty of ridicule.

Pep Guardiola, at Man City, wore a black DSquared2 number for a while, slightly more formal than something by Nike or Adidas. Jupp Heynckes stayed warm in his final season at Bayern Munich in an Adidas puffer: it had six partitions, his initials on one side and the club crest over his heart. In England, Roy Hodgson's Puma parka had Crystal Palace's crest on the left breast; so did Ole Gunnar Solskjær at United, though his was Adidas and cut shorter.

It could it be that the "coaches' cut" was ahead of its time. Limited mostly to the pitch in London, long parkas now litter catwalks in Milan and Paris. It seems every fashion house has made one. There is a shiny down Valentino (about $2,400), and a Moncler version (about the same price). Balenciaga has one ($3,500), the biggest of the bunch, and Vetements made a sleeping bag coat ($3,850) -- both designed by Georgia native Demna Gvasalia, who included soccer scarves in his other collections. (There's even a parka named the Wenger, by Martine Rose, a designer from south London.)

So it makes sense fashion is picking up the slack, producing memorable, useful jackets that get second looks. But it is puzzling that the most unique piece of merchandise in soccer is so unattainable to fans.

Nike, New Balance, Puma and Adidas make longer soccer-cut parkas without branding, in different colors, but mostly for the East Asian market, and free of club logos. There are no long parkas for sale at Arsenal's online shop -- and Wenger-cut jackets were pulled from the Arsenal store for lack of demand in 2013 -- and I've never seen one at a vintage store in Paris, New York or at a flea market anywhere. Felix Dean, a London dealer who specializes in vintage sportswear, sold a few, including an Arsenal one, but says they're "rarely seen when I'm out and about digging for stock." James Ritter, who runs Joint Custody, a vintage store in Washington D.C., says he runs across a good amount of 2000s Nike jackets -- "a tough look" -- but "not the team ones."

In the end, that rarity brings cachet. It's a tease to not have the real thing, but it's not impossible to get a club parka. They're out there, like colored cleats used to be, in small numbers. Diehard fans wear long parkas to matches, around London, in Europe. I've seen a few in New York (Brazil, USMNT to name just two) and in the course of reporting, several online, even a "Wenger." The coolest item in soccer isn't sold in stores, or for every club, but it's still for sale. Maybe just go on eBay. It's about winning, isn't it?